Images panel

Change the PDF compatibility in the Images panel of the PDF
Optimizer dialog box.

Specify the following
options, as needed:

Downsample

Reduces file size by lowering the resolution of images, which involves
merging the colors of original pixels into larger pixels.

Note: Masked
images and images with a size less than 16-by-16 pixels are not downsampled.

Compression

Reduces file size by eliminating unnecessary pixel data.
In general, JPEG and JPEG 2000 compression give better results on
images like photographs with gradual transitions from color to color.
ZIP is the better choice for illustrations with large areas of solid,
flat color, or patterns made up of flat colors. For monochrome images,
JBIG2 compression, which is available in PDF Optimizer but not in
Distiller, is superior to CCITT.

Quality

Available only for JPEG and JPEG 2000 formats. JPEG and JPEG
2000 compression methods are typically lossy, a process
that permanently removes some pixel data. You can apply lossy JPEG
or JPEG 2000 compression to color images at various levels (minimum,
low, medium, high, maximum). For JPEG 2000 compression, you can
also specify lossless so that no pixel data is removed. Compression
for monochrome images is lossless, except for JBIG2 compression, which
provides both lossy and lossless modes of compression.

Tile Size

Available only for JPEG 2000 format. Divides the image being compressed
into tiles of the given size. (If the image height or width is not
an even multiple of the tile size, partial tiles are used on the
edges.) Image data for each tile is individually compressed and
can be individually decompressed. The default value of 256 is recommended.

Optimize Images Only If There Is A Reduction In Size

When selected, if the image setting will cause an increase
in file size, the optimization for that image is skipped.

Fonts panel

To ensure an exact match to the source document,
it’s a good idea to embed all fonts used in the document. If you
don’t need an exact match and you prefer a smaller file, you can
choose not to embed fonts for roman text and East Asian text (Traditional
Chinese, Simplified Chinese, Korean, and Japanese). Text in these languages
is replaced with a substitution font when viewed on a system that does
not have the original fonts. The Fonts panel of the PDF Optimizer
contains two lists for fonts: fonts that are available for unembedding,
and fonts to unembed. Certain fonts aren’t available for unembedding
and don’t appear in the Fonts panel. To unembed fonts in a document,
select one or more fonts in the Embedded Fonts list, and click the
Unembed button. If you don’t want to embed subsets of the embedded
fonts, deselect Subset All Embedded Fonts. To prevent unembedding
for all fonts in the document, select Do Not Unembed Any Font.

Transparency panel

If your PDF includes artwork that contains
transparency, you can use presets in the Transparency panel of PDF
Optimizer to flatten transparency and reduce file size. (Flattening
incorporates transparency into corresponding artwork by sectioning
it into vector-based areas and rasterized areas.) PDF Optimizer
applies transparency options to all pages in the document before
applying other optimization options.

If you select the Acrobat
4.0 And Later compatibility setting, the Transparency panel is enabled
and all transparency in the file is flattened during optimization. This
ensures compatibility with Acrobat 4.0 and earlier, which doesn’t
support transparency.

When you create flattening presets,
they appear with the default presets in the Transparency panel.

Note: Transparency
flattening cannot be undone after the file is saved.

Discard Objects panel

The
Discard Objects panel lets you specify objects to remove from the
PDF and lets you optimize curved lines in CAD drawings. You can
discard objects created in Acrobat and in other applications. Selecting
an object removes all occurrences of that object within the PDF.

In
the Discard Objects area, you can select from these and other options:

Discard All Form Submission, Import And Reset Actions

Disables all actions related to submitting or importing form
data, and resets form fields. This option retains form objects to
which actions are linked.

Flatten Form Fields

Makes form fields unusable with no change to their appearance.
Form data is merged with the page to become page content.

Discard All JavaScript Actions

Removes any actions in the PDF that use JavaScript.

Discard All Alternate Images

Removes all versions of an image
except the one destined for on-screen viewing. Some PDFs include
multiple versions of the same image for different purposes, such
as low-resolution on-screen viewing and high-resolution printing.

Discard Embedded Page Thumbnails

Removes
embedded page thumbnails. This is useful for large documents, which
can take a long time to draw page thumbnails after you click the
Page Thumbnails button.

Discard Document Tags

Removes
tags from the document, which also removes the accessibility and
reflow capabilities for the text.

Convert Smooth Lines To Curves

Reduces the number of control points
used to build curves in CAD drawings, which results in smaller PDF
files and faster on-screen rendering.

Detect And Merge Image Fragments

Looks for images or masks that are fragmented
into thin slices and tries to merge the slices into a single image
or mask.

Discard Embedded Print Settings

Removes embedded print settings, such as page scaling and
duplex mode, from the document.

Discard Embedded Search Index

Removes embedded search indexes, which reduces file size.

Discard Bookmarks

Removes all bookmarks from the document.

Discard User Data panel

Use the Discard User Data panel to remove any
personal information that you don’t want to distribute or share
with others. If you’re unable to find personal information, it may
be hidden. You can locate hidden text and user-related information
by using the Examine Document command (Tools > Protection >
Remove Hidden Information).

Discard All Comments,
Forms And Multimedia

Removes all comments, forms, form fields, and multimedia
from the PDF.

Discard Document Information And Metadata

Removes information in the document information dictionary
and all metadata streams. (Use the Save As command to restore metadata
streams to a copy of the PDF.)

Removes links to other documents. Links that jump to other
locations within the PDF are not removed.

Discard Private Data Of Other Applications

Strips information from
a PDF document that is useful only to the application that created
the document. This does not affect the functionality of the PDF,
but it does decrease the file size.

Discard Hidden Layer Content And Flatten Visible Layers

Decreases file size. The optimized document looks like the
original PDF but doesn’t contain layer information.

Clean Up panel

The options in the Clean Up panel of the PDF
Optimizer remove useless items from the document. These items include
elements that are obsolete or unnecessary for your intended use
of the document. Removing certain elements can seriously affect
the functionality of the PDF. By default, only elements that do
not affect functionality are selected. If you are unsure of the
implications of removing other options, use the default selections.

Object Compression Options

Specifies how to apply Flate compression in the file.

Use Flate To Encode Streams That Are Not Encoded

Applies Flate compression to all streams that aren’t encoded.

In Streams That Use LZW Encoding, Use Flate Instead

Applies Flate compression to all content streams and images
that use LZW encoding.

Discard Invalid Bookmarks

Removes bookmarks that point to pages in the document that
have been deleted.

Discard Invalid Links

Removes links that jump to invalid destinations.

Discard Unreferenced Named Destinations

Removes named destinations that are not being referenced
internally from within the PDF document. Because this option does
not check for links from other PDF files or websites, it does not fit
in some workflows.